According to usatoday.com, Burger King teamed up with the Paramount Trials and Florida Sleep & Neuro Diagnostic Services to conduct a sleep study. They had participants eat a "Nightmare King" to see if the sandwich would give them nightmares.

“'According to previous studies, 4 percent of the population experiences nightmares in any given night,' said Dr. Jose Gabriel Medina, the study’s lead doctor, in a statement. 'But, after eating the Nightmare King, the data obtained from the study indicated that the incidence of nightmares increased by 3.5 times.'”

So, according to the study, eating a "Nightmare King"can actually give you nightmares!